Background & objectives: Presence of dengue is reported from India since 1960s. Secondary dengue infection may be more severe than primary, hence, distinction between primary and secondary dengue is essential. A way to detect secondary dengue is demonstration of anti DV IgG in patients' serum. In this study we explored the association of dengue severity with anti DV IgG positivity.
Methods: Laboratory confirmed cases of dengue (positive for anti DV IgM/ NS-1 Antigen/ DV -RNA), presenting to the hospital within 7 days of illness, were consecutively enrolled for a period of one month (September 1-30, 2018) and were tested for anti DV IgG in their serum. All PCR positive samples were serotyped. Cases positive for anti-dengue IgG were labeled as secondary cases. Clinical details were collected to assess the severity of illness. Association of dengue severity with anti DV IgG positivity was calculated.
Results: Of the 128 dengue positive cases, 89 (69.5%) were anti DV IgM positive, 72 (56.3%) were Dengue NS-1 positives and 37 (28.9%) were DV-RNA positive. Only 39 (30.5%) cases were having detectable anti-dengue IgG in their serum (secondary dengue). Anti-dengue IgM positivity was significantly higher in secondary dengue cases. No association of anti DV IgG positivity was seen with severity of dengue illness.
Interpretation & conclusion: No association of IgG positivity with severity of illness was seen. D4 serotype is first time reported from Uttar Pradesh, India.
Keywords: Anti Dengue IgG; Dengue Severity; Dengue serotypes; Primary dengue; Secondary dengue; Dengue serotypes.